초록 ▼

A flexible member sensor for detecting motion and tension of a flexible member includes a rigid member pivotally connected to a base, in contact with the flexible member. A sensor detects pivotal motion of the rigid member in response to movement of the flexible member. The sensor may provide a corr

A flexible member sensor for detecting motion and tension of a flexible member includes a rigid member pivotally connected to a base, in contact with the flexible member. A sensor detects pivotal motion of the rigid member in response to movement of the flexible member. The sensor may provide a corresponding signal to a motion control system that adjusts the tension of the flexible member accordingly. In one implementation, the flexible member sensor is integrated with a feedback control system for an electric seat belt retractor that includes a feedback control loop. The flexible member sensor measures tension in seat belt webbing retained by the retractor. A motor coupled to a servo amplifier rotates a spool of the electric retractor to extract or retract webbing in accordance with the output of the flexible member sensor. The seat belt tension may thus be continuously maintained at a desired level.

대표청구항 ▼

1. A flexible member sensor, comprising:a rigid member pivotally connected to a retractor frame, wherein seat belt webbing is retracted into and extracted from the retractor frame; a sensor in communication with the rigid member to detect movement of the rigid member relative to the retractor frame,

1. A flexible member sensor, comprising:a rigid member pivotally connected to a retractor frame, wherein seat belt webbing is retracted into and extracted from the retractor frame; a sensor in communication with the rigid member to detect movement of the rigid member relative to the retractor frame, the sensor providing a signal corresponding to movement of the rigid member; wherein the rigid member communicates with the seat belt webbing such that changes in tension within the seat belt webbing cause the rigid member to pivot to a position substantially perpendicular to the seat belt webbing when there is substantially no tension in the seat belt webbing and pivots away from a perpendicular angle with the seat belt webbing when there is tension in the seat belt webbing. 2. The flexible member sensor of claim 1, wherein the rigid member comprises an arm having a pivot end and a contact end and wherein the seat belt webbing contacts the arm at the contact end and traverses the length of the arm to pass in close proximity to the pivot end.3. The flexible member sensor of claim 2, wherein the contact end comprises a passage through which the seat belt webbing is threaded.4. The flexible member sensor of claim 1, further comprising a spring that biases the rigid member to pivot towards the retractor frame.5. The flexible member sensor of claim 1, wherein the sensor comprises an angular sensor that provides the signal based on the position of the rigid member relative to the retractor frame.6. The flexible member sensor of claim 1, wherein the sensor detects acceleration of the rigid member from a first position to a second position and provides a corresponding signal based on the acceleration.7. The flexible member sensor of claim 1, wherein the signal controls retraction and extraction of the seat belt webbing in an electric seat belt retractor.8. The flexible member sensor of claim 1, wherein the sensor is integrated with a guide for the seat belt webbing.9. The flexible member sensor of claim 1, wherein the sensor is mechanically coupled to the rigid member.10. A feedback control system for controlling an electric seat belt retractor comprising:a spool connected to seat belt webbing wound around the spool, the spool being rotatable about an axis fixed within a retractor frame, wherein the retractor frame comprises a belt opening at one end of the retractor frame which allows extraction and retraction of the seat belt webbing from the retractor; a tension sensor in communication with a portion of the seat belt webbing that extends from the retractor frame, the tension sensor measuring tension in the seat belt webbing between the extended portion and the spool, wherein the tension sensor comprises an arm, one end of the arm being pivotally attached to the retractor frame, wherein the arm extends over the belt opening and pivots to substantially cover the belt opening when there is substantially no tension in the seat belt webbing and pivots to about a ninety degree angle with respect to the belt opening when tension in the seat belt webbing causes the seat belt webbing to extend substantially perpendicular to the retractor frame; an electric motor coupled to the spool to rotate the spool about the axis; and a servo amplifier electrically connected to the tension sensor and the electric motor such that a change in tension measured by the tension sensor causes the servo amplifier to provide a corresponding voltage to the motor which adjusts tension in the seat belt webbing until a predetermined tension is measured by the tension sensor. 11. The feedback control system of claim 10, wherein the tension sensor comprises:the other end of the arm having a webbing passage through which the portion of the seat belt webbing extending from the belt opening is threaded. 12. The feedback control system of claim 10, wherein when the arm pivots to form an angle with the belt opening of between about zero and about forty-five degrees, the tension sensor provides a retraction voltage to the servo amplifier such that the motor is activated to retract the seat belt webbing onto the spool.13. The feedback control system of claim 10, wherein when the arm pivots to form an angle with the belt opening of between about forty-five degrees and about ninety degrees, the tension sensor provides an extraction voltage to the servo amplifier such that the motor is activated to extract the seat belt webbing from the spool.14. The feedback control system of claim 10, wherein when the arm pivots to form an angle with the belt opening of about forty-five degrees, the tension sensor provides no voltage to the servo amplifier such that the motor is deactivated.15. The feedback control system of claim 10, wherein the tension sensor comprises a potentiometer that provides a retraction voltage, an extraction voltage and substantially no voltage based on the position of the arm with respect to the belt opening.16. The feedback control system of claim 10, wherein the tension sensor comprises a spring which biases the arm towards the belt opening.17. The feedback control system of claim 10, wherein the tension sensor is a web guide for the electric seat belt retractor.18. The feedback control system of claim 10, wherein the servo amplifier is a voltage amplifier.19. The feedback control system of claim 10, wherein the predetermined tension is between about two Newtons and about four Newtons.20. A feedback control system for controlling an electric seat belt retractor comprising:a spool connected to a seat belt webbing wound around the spool, the spool being rotatable about an axis fixed within a retractor frame; a direct current electric motor coupled to the spool to rotate the spool about the axis; a web guide pivotally connected to a belt opening of the retractor frame, the web guide being in communication with the seat belt webbing such that tension in the seat belt webbing extending from belt opening causes the web guide to pivot with respect to the retractor frame; and a servo amplifier electrically connected to the web guide and the electric motor, the servo amplifier receiving an input voltage from the web guide, the input voltage being determined by the angular position of the web guide with respect to the belt opening, wherein the servo amplifier provides an output voltage to the motor to adjust the tension in the seat belt webbing in response to the input voltage. 21. The feedback control system of claim 20, wherein the web guide comprises:an arm which extends from the belt opening, the arm being pivotally attached to the retractor frame, the other end of the arm having a webbing passage through which a portion of the seat belt webbing extending from the belt opening is threaded; wherein the arm pivots to substantially cover the belt opening when there is substantially no tension in the seat belt webbing and pivots to about a ninety degree angle with respect to the belt opening when there is tension in the seat belt webbing extending from the retractor frame. 22. The feedback control system of claim 21, wherein when the arm pivots to form an angle with the belt opening of between about zero and about fort-five degrees, the input voltage to the servo amplifier producing an output voltage which activates the motor to retract the seat belt webbing onto the spool.23. The feedback control system of claim 22, wherein when the arm pivots to form an angle with the belt opening of between about forty-five degrees and about ninety degrees, the input voltage to the servo amplifier producing an output voltage which activates the motor to extract the seat belt webbing from the spool.24. The feedback control system of claim 23, wherein when the arm pivots to form an angle with the belt opening of about forty-five degrees, the input voltage to the servo amplifier producing an output voltage of about zero volts such that the motor is deactivated.25. The feedback control system of claim 23, wherein the amount of tension in the seat belt webbing which causes the motor to be deactivated is between about two Newtons and about four Newtons.26. The feedback control system of claim 20, wherein the web guide comprises a potentiometer that provides an input voltage to the servo amplifier which varies based on the angular position of the web guide with respect to the belt opening.27. The feedback control system of claim 26, wherein the web guide is connected by a pivot to the retractor frame and the potentiometer is connected to the pivot such that movement of the web guide about the pivot varies the voltage provided by the web guide to the servo amplifier.28. The feedback control system of claim 20, wherein the angular position of the web guide with respect to the belt opening determines the magnitude and the polarity of the input voltage.29. The feedback control system of claim 20, wherein the web guide comprises a spring which biases the arm towards the belt opening.30. The feedback control system of claim 20, wherein the servo amplifier is a voltage amplifier.31. A feedback control system for controlling an electric seat belt retractor comprising:a spooling means for spooling and paying out seat belt webbing for a seat belt retractor; a power means coupled to the spooling means for automatically paying out and retracting seat belt webbing from the seat belt retractor; and a sensor means in communication with the seat belt webbing for continuously sensing tension in the seat belt webbing, the sensor means being in communication with the power means such that when tension in the seat belt webbing is outside a predetermined range the sensor means provides a signal to directly and continuously adjust the power means to adjust the tension in the seat belt webbing until the tension is within the predetermined range. 32. A feedback control system of claim 31, wherein the predetermined range is between about two Newtons and about four Newtons.